Open Veterinary Journal, (2026), Vol. 16(6): 3304-3310

Review Article

10.5455/OVJ.2026.v16.i6.2

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Feeding time and feeding frequency: Mechanism and effect on poultry production

Nguyen Hoang Qui^* and Nguyen Thuy Linh

Department of Animal Science and Veterinary Medicine, School of Agriculture—Aquaculture, Tra Vinh University, Vinh Long Province, Vietnam

*Corresponding Author: Nguyen Hoang Qui. Department of Animal Science and Veterinary Medicine, School of Agriculture—Aquaculture, Tra Vinh University, Vinh Long Province, Vietnam. Email: nhqui [at] tvu.edu.vn

Submitted: 23/11/2025 Revised: 22/04/2026 Accepted: 03/05/2026 Published: 05/06/2026

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Abstract

Feeding timing and feeding frequency (FTF) are important management aspects affecting physiological regulation, nutrient utilization, and productivity in poultry. While ad libitum feeding continues to be common in production, there is increasing evidence that the timing of feeding and timing matching with circadian rhythm, i.e., feeding into several meals, can enhance growth, reproduction efficiency, and adaptation to environmental challenges. This review aims to consolidate the current understanding of how FTF affects gut development, hormone secretion, metabolic balance, and stress response. Biologically ideal feeding at different times of day has been shown to improve the functioning of the gastrointestinal system, enhance the action of anabolic hormones, increase feed intake in cooler weather, and attenuate the heat-induced depression in growth. On the other hand, increasing feeding frequency promotes ongoing nutrient uptake, stabilizes blood metabolism, increases muscle protein accumulation, and decreases aggressive behavior related to feed competition. Taken together, these mechanisms enhance the daily average increase, feed conversion ratio, and flock uniformity. In addition to growth, FTF has effects beyond growth on reproduction itself, via greater energy balance, metabolic stability, and better ovarian activity synchronization. Suitable FTF techniques are required to ensure good intestinal integrity, antioxidant performance, and overall physiological stability in the intestines under heat stress. Nonetheless, responses to FTF are contextually contingent and depend on genetics, age, production-related features, environment, and production purpose, while context-specific management is required for optimal use. This review provides a physiological basis for understanding FTF, serving as a foundation for developing precision feeding strategies that can be used to formulate fine mechanical precision feeding programs to achieve greater efficiency and welfare, that is, sustainably in today’s poultry production.

Keywords: Circadian rhythm, Feeding frequency, Feeding time, Heat stress, Poultry production.

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Introduction

Poultry production is one of the fastest growing sectors in the global livestock industry as a vital aspect that provides animal protein for humans (Castro et al., 2023). In particular, chickens are the largest species of poultry, accounting for significant quantities of meat and eggs, supporting food security and livelihood support to millions of farmers in urban economies and rural areas alike (Van Dijk et al., 2021). Many modern technologies have been used in tandem with production scale intensification and extension to optimize production efficiency. Automatic feeding through the machine is common, as is precision sensing and real-time monitoring to adjust feed allocation, feed intake monitoring, and flock uniformity. These developments aid farmers in controlling the amount of nutrients delivered (Natsir et al., 2025), reducing labor costs, and maximizing sustainability in poultry production.

The feeding systems of the abovementioned technologies continue to be an influential factor in livestock production efficiency. Of these fundamental factors, feeding time and feeding frequency (FTF) are closely related to the feeding behavior, digestive physiology, and metabolic responses of poultry. Although numerous experimental studies have shown the potential advantages of FTF, ad libitum feeding remains the predominant practice in commercial poultry production due to its simplicity, low labor requirement, and robustness across diverse management conditions. The practical application of FTF is constrained by several factors, including increased management complexity, dependence on precise lighting and environmental control, variability in responses among genotypes and production stages, and the risk of reduced feed intake or uneven growth when feeding schedules are improperly designed. Chickens exhibit a circadian system that regulates feeding, energy, and hormones. Previous studies suggest that this control system is relevant for hormone secretion, metabolism, immunity, and musculoskeletal development (Tähkämö et al., 2019). Consequently, the timing and number of meals per day can profoundly affect both growth and reproduction. Feeding the right amount of time to improve feeding behaviors and nutrient absorption enhances growth rate and feed efficiency (Azis and Afriani, 2023; Li et al., 2023). Moreover, feeding frequency is important for a firm nutrition supply level, minimizing competition from other flocks, lower stress, higher uniformity, and improved reproductive characteristics such as laying rate, egg quality, fertility, and hatchability (Liu et al., 2020; Aziz and Masoud, 2021; Wang et al., 2024). However, the influence of FTF remains neglected in most of the existing production processes, as most flocks are fed ad libitum irrespective of the birds’ circadian rhythm. FTF is known to improve the growth rate, feed conversion ratio (FCR), and uniformity of body weight within the flock (Aziz and Masoud, 2021; Chaiyasing et al., 2024; van Emous et al., 2024; Wang et al., 2024). In laying hens, variation in feeding times influences the laying rate, egg weight, and shell quality, and feeding frequency is related to reproductive cycle stability (Soltanmoradi et al., 2013; van Emous and Mens, 2021). Second, FTF has been identified as another determinant of the physiological responses to stress, particularly heat stress (Kennedy et al., 2022; Bhawa et al., 2023), one of the key challenges faced by the poultry industry. When exposed to high temperatures, the feeding time distribution can decrease the level of cortisol activity by maintaining feed intake for better chicken survival (Bhawa et al., 2023).

Therefore, this review aims to systematically synthesize the current knowledge on the mechanisms and effects of FTF on poultry growth performance, reproductive efficiency, and stress adaptation. The physiological mechanisms underlying circadian rhythm regulation, nutrient metabolism, and environmental stress responses are given special attention to provide practical insights for precision feeding management in poultry production systems. FTF optimization has been implicated not only in boosting growth rate, FCR, and reproductive performance but also in reducing heat stress, reducing nutrient oversupply, and improving gut health. While a number of recent studies have shown that FTF can improve growth and reproductive performance through the correct adjustment of different climatic conditions and production systems, the results are limited, fragmented, and not systematically integrated. Hence, thorough and accurate studies are required to characterize the mechanisms of action and opportunities for the use of FTF in poultry production.

Mechanism of FTF

Physiological mechanisms of feeding time

Feeding timing influences poultry productivity by closely aligning with the circadian rhythm, the biological cycle that regulates nutrient consumption, digestion, and metabolic functions. A circadian rhythm is a biological phenomenon that refers to the internalization of biological changes that last approximately 24 hours per day (Halberg et al., 1959). Today, we consider that the circadian rhythm regulates gene expression in many tissues and synchronizes different biological processes to cycle around a 24-hour period (Song et al., 2021). Poultry have a unique and strong circadian rhythm and activity, and rest pattern when they are mainly active during the day. According to Moss et al. (2023), the circadian system strongly influences bird feeding behavior; however, night-time feed intake may still occur depending on lighting programs (e.g., intermittent or extended photoperiods), light intensity, and management, and therefore should not be considered universally absent. The most active time of day, especially the morning and late afternoon, can be expected to yield a good performance. In commercial hatcheries, there is usually a longer time interval between hatching and the first feed provided because of the variability in hatching times between the eggs. Thus, early-hatched chicks are disadvantaged because they are subjected to prolonged fasting and are more likely to be dehydrated (Proszkowiec-Weglarz et al., 2022). Outside the cell, biological circadian rhythms regulate the health and processes of the digestive tract, including cellular proliferation, motility, and digestion (Voigt et al., 2019). Feeding time in poultry acts as a powerful external cue that synchronizes peripheral circadian clocks, particularly in metabolic and digestive tissues. Therefore, inappropriate feeding schedules may disrupt circadian alignment, resulting in suboptimal nutrient use and physiological stress.

In addition, poultry that are fed during high phases of physical activity tend to function better, producing more anabolic hormones, such as insulin-like growth factor 1 (IGF-1) and growth hormone. As these hormones expand, they trigger an increase in muscle protein generation and tissue growth, resulting in higher growth rates and body weight gain (Fujita et al., 2017). According to Sun et al. (2023) and Qin et al. (2023), feeding in the cooler hours of the day helps prevent the effect of heat stress, but more so in hot climates. Heat stress impedes broiler growth, reduces feed consumption, and enhances mortality. This can be because birds feed at lower ambient temperatures, which allows them to eat more feed, minimize energy loss for thermoregulation, and use nutrients better for growth.

Feed time is critical for reproductive performance and modulates the secretion of reproductive hormones and the ovulatory cycle. Given that egg yield and feed consumption decreased as a result of heat stress in laying hens, feeding at an adequate temperature promotes reproductive activity (Mazzoni et al., 2022). Therefore, the timing of feeding should be improved, especially in the early morning or late afternoon, to reduce heat stress. A circadian rhythm-consistent feeding strategy for hens is a split meal of two meals per day to achieve more accurate feed quality distribution and to adapt food requirements to the essential biological characteristics of birds (Moss et al., 2023), thereby improving reproductive performance in hens. Thus, in low-temperature times, such as early hours of the day and late hours of the evening, a great deal of the feed should be provided to poultry (Bhawa et al., 2023). Feeding in the early morning is also preferred to prevent body heat production at high temperatures. Thus, hens should typically be fed from 06:00 to 07:00 so that heat from nutrient metabolism is released before the daily heat peak (Moradi et al., 2013).

First, feeding more than one meal helps stabilize blood sugar and amino acids in the muscle; hence, the body can continuously produce muscle protein and avoid long periods of fasting that can lead to metabolic disturbances (Wang et al., 2024). Second, the more often we eat, the better our digestive enzymes act in the digestive system and the faster the gizzard develops, which can better grind feeds and absorb nutrients. Third, a combination of meals helps to decrease feeder competition, thus relieving competitive stress at the feeder and reducing social stress and energy loss, and hence aggression-associated loss due to aggression. Many studies on feeding behavior and intervention have noted and discussed these mechanisms (Wang et al., 2024).

Physiological and behavioral feeding frequency mechanisms

Feeding frequency is one of the main factors contributing to the efficient use of nutrients, behavior, and welfare of poultry. Feeding frequency is a feed restriction strategy. When the ration is broken down into many small daily feedings (i.e., small times per meal), nutrient availability is stabilized by decreasing competitive actions during feeding periods, increasing the likelihood that poultry will feed in a lower stress environment. Feeding frequency influences body weight gain via nutrient digestion, absorption mechanisms, and energy distribution and storage (Chastanet et al., 2007). Frequent feeding can also encourage the secretion of pancreatic juice, thus stimulating the normal digestive process and nutrient absorption (Jia et al., 2021). With regard to growth and metabolic mechanisms, eating multiple bite-sized meals throughout the day helps to guarantee an even balance between metabolic homeostasis and amino acid levels, producing optimal conditions for sustained muscle protein formation. According to Taherkhani et al. (2010), regular feeding intervals would allow the blood glucose levels to be steady, as it is vital to keep reproductive processes and weight gain under control, which decreases fat deposition in the body. The constant supply of this energy and sustenance supports a more steady weight gain relative to feeding with fewer meals. As an example, when it comes to digestion and the absorptive body, an efficient way to increase digestive enzymes that contribute so much to digestion is through several feedings and frequent eating. Feeding is equally beneficial for intestinal motility, digestive disturbances, and the pro-growth of healthy gut microbiota (Wang et al., 2018). Repeated feeds minimize feeder competition, which leads to a decreased number of fights and aggressive actions of the animals in the pasture. Less-pressure competition means less time left over for digestion, and growth is spent on aggressive feeding behaviors (Wang et al., 2024) for poultry and food management. This also enhances animal welfare by minimizing the potential for injury or stress in the flock due to social conflict.

The rapid growth rate in broilers has resulted in health problems, and higher nutrient supplies result in increased fat deposition. Hence, feed restriction is implemented to control these problems. Feed restriction can manage body growth and some metabolic disorders related to the rapid growth rates of genetic lines of broiler chickens (Butzen et al., 2013). Likewise, restricted feeding is favored to enhance broiler production performance and increase heat stress resistance (Xie et al., 2015). Rapid growth and high feed efficiency are two key factors for effective broiler production. A high growth rate of broilers can be expected when chickens are fed ad libitum and their disease is controlled with continuous lighting (Adikari et al., 2018). Unfortunately, ad libitum-fed chickens were found to have an increased rate of mortality and metabolic diseases. Feeding more than chicken maintenance and production requirements led to increased feed wastage and feed costs, as well as reduced carcass quality (Mehmood et al., 2013).

Effects of FTF on the growth performance of poultry

FTF also leads to obvious differences and has significant impacts on chicken growth performance. Numerous experimental studies have demonstrated that early post-hatch feeding enhances intestinal development, increases villus height, promotes the expression of tight-junction proteins, and increases anabolic hormones, such as IGF-1, to help increase early growth and possibly contribute to the final body weight (Wang et al., 2018; Chaiyasing et al., 2024). These findings were reported in studies of the effects of first feeding time on chicken growth and gut traits (Wang et al., 2018). Regarding the question of feeding frequency, several experimental findings reveal that dividing the ration up in ≥2 meals/day (vs. one meal/day) tends to enhance total feed intake, body mass gain, and FCR (Chaiyasing et al., 2024), but only in terms of how far the ration is divided between meals and the combined dietary energy. The experimental application demonstrated that feeding twice in equal portions was significantly more positive for average daily weight and FCR than feeding once. Precision feeding approaches (or AM/PM split feeding) optimize nutrient supply for the daily phase and improve feed efficiency (Aziz and Masoud, 2021). Three physiological and behavioral factors underlie these effects (Wang et al., 2024).

However, there is no assurance that feeding frequency or feeding length will yield the full benefits. Time-restricted feeding (TRF) has been shown to lower total feed intake and increase a large number of healthy performance indicators along with energy efficiency (Azis et al., 2019; Saibaba et al., 2021). This shows trade-offs between nutrition efficiency (across all nutrients), feed intake, and production goals (rapid growth versus long-term health). TRF results in laying hens indicate that FCR and other production parameters are not affected by feed intake, indicating that birds vary physiologically under various feeding modes (Saibaba et al., 2021). Moreover, the practical use of FTF is highly species or strain-dependent, depending on age, production system (broiler, layer, or breeder), environmental temperature, and feed quality (Anene et al., 2023). The obvious advantages of feeding in the early stages of the post-hatch phase occur in the starter phase, which is compensated for with increased input from other young birds if appropriate nutritional and environmental conditions are achieved. Therefore, in the production of FTF, a proper strategy for FTF should be evaluated based on the objective of FTF (such as growth maximizing, flock uniformity, or cost optimization). Thus, frequent feeding can also maintain a stable energy supply and amino acids to feed muscles and promote body weight growth (Wang et al., 2024).

Chickens fed multiple meals per day consume more feed than those fed TRF models (Aziz and Masoud, 2021). The evidence by Chaiyasing et al. (2024) further corroborated that higher feeding frequency increases FCR through the decrease of feed waste and the shorter interval between meals, decreasing the competition between animals, hoarding behavior, and feeding behavior. Development of the digestive system is also essential. Thus, for chickens fed multiple small meals, the odds of having stronger gizzard activity, higher gizzard activity, feed grinding capacity, and more digestibility increase (Wang et al., 2018). Under these conditions, regular and constant nutrient supply increases microbial activity in the gut, leading to better gut health and growth.

Effects of FTF on poultry reproductive performance

FTF are largely responsible for regulating reproduction in poultry. They regulate energy metabolism, regulate reproductive hormones, and maintain a suitable physiological state for reproduction. Adjustments in feeding time immediately impact the circadian rhythm of laying hens, which ultimately impacts the ovulation cycle, eggshell development, and laying time. Therefore, feeding supply can provide balanced and reliable secretion of luteinizing hormone and follicle-stimulating hormone that aids follicle maturation (Moss et al., 2023) and helps speed the ovulation rate by being synchronized with the peak periods of daily activity. In addition, feeding in the early morning and late afternoon reduces feed intake due to higher environmental temperature, resulting in better energy expenditure for egg formation.

In addition, feeding frequency significantly affects egg formation by energetically stabilizing the energy required for egg formation. Once the ration is divided into a series of small meals, nutrient availability and amino acid levels are maintained at least a little bit at the end of each meal. This provides a better environment for building albumen, shell membranes, and eggshell calcification. Regular feeding also facilitates irregular development and fertilization of ovarian follicles. Soltanmoradi et al. (2013) have revealed that a higher feed-in frequency results in a better size distribution of the follicles, a higher number of preovulatory follicles, and better ovulation. FTF contributes to improved energy availability necessary for egg development and shell quality, thereby improving embryo viability and hatchability. Feeding twice is beneficial for egg laying and fertility and decreases the pelvic body fat content in breeder hens (Taherkhani et al., 2010). However, feeding in one sitting can lead to an increased fluctuation of glucose and excessive deposition of fat, along with a negative impact on the organs, particularly ovarian function. Soltanmoradi et al. (2013) further indicated that higher feed rates increase fertility and hatchability due to reduced nutritional stress and improved egg quality. Soltanmoradi et al. (2013) reported that frequent feeding enhances hatchability and viability of embryos as a result of decreased energetic fluctuations and regulation of reproductive hormone balance. In addition to egg production, FTF can affect the quality of eggs. Multiple foods keep blood amino acids and minerals stable and can help form albumen and mineralize the eggshell. Moradi et al. (2013) found that when feeding frequency increased in breeder hens, the shell thickness and quality index improved due to increased lipid and calcium metabolism. Moreover, the hens that are fed in cooler periods of the day have a relatively greater feed intake during heat stress, and this can prevent the decline in the eggshell, which would occur under extreme heat (Mazzoni et al., 2022).

Additionally, if feeding times are adjusted properly under heat stress conditions, the decline in egg production and shell health can be decreased, which is difficult to achieve when heat stress suppresses calcium mobilization and calcification. Mazzoni et al. (2022) showed that the higher the feeding frequency at high temperatures, the better the egg production and the condition of the eggshell, as the activity of the shell glands remains. This study demonstrates that FTF is a good management tool for sustaining reproductive performance in adverse situations. From a practical perspective, FTF optimization represents an effective management strategy for breeder flocks. Properly scheduled feeding can enhance follicular synchronization, improve eggshell quality, and maintain fertility under both normal and heat stress conditions, thereby contributing to more stable and predictable reproductive performance.

Effect of FTF on stress management

Notably, the relevance of heat stress discussed in this review varies across production systems. Thermal conditions are generally well managed in large-scale commercial farms equipped with advanced climate-control technologies, and the direct impact of heat stress may be less pronounced. In contrast, many studies have examined FTF in tropical regions, small- to medium-scale farms, or production systems with limited environmental control, where heat stress remains a major constraint (Xie et al., 2015; Bhawa et al., 2023). Therefore, the emphasis on heat stress in this review reflects the prevailing conditions under which much of the existing evidence has been generated, rather than implying universal applicability across all poultry production systems. FTF is related to stress management, particularly heat stress, which is one of the predominant causes of economic loss in the poultry industry in hot–humid climates. First, the timing of feeding may be positively correlated with poultry adaptation to temperature. Food processing generates heat under more favorable environmental conditions when feed is delivered during cooler hours of the day (early morning and late afternoon), minimizing the risk of excessive body heat. Bhawa et al. (2023) emphasized optimal feeding timing, which can reduce plasma cortisol and feeding sustenance under heat conditions (increasing heat stress tolerance). This involves increasing the number of feed times per day to help reduce physiological stress and prevent a bingeing period. By breaking the ration into small meals, poultry can avoid eating too quickly or staying hungry for too long, both of which can trigger metabolic stress. According to Xie et al. (2015), heat-stressed broilers fed limited feed in small, multiple meals had lower stress hormones and higher antioxidant status than those fed ad libitum.

Furthermore, the appropriate use of FTF enhances flock uniformity and reduces competition and behavioral conflicts at the feeder, which is also conducive to reducing social stress, one of the most common causes of immunosuppression and decreased productivity. Consistent nutrient provision via higher feeding frequency facilitates intestinal barrier stability and minimizes changes to gut microbiota, which are frequent results of heat stress. More recent studies (Mazzoni et al., 2022; Qin et al., 2023) have reported that heat stress damages the intestinal mucosa, decreases villus height, and increases intestinal permeability. Routine feed addition attenuates such injuries by maintaining intestinal motility and providing energy for epithelial recovery. Consequently, FTF is not only a productivity management tool but also an important measure for improving animal welfare and health in increasingly harsh climatic conditions.

FTF may also mitigate other forms of stress, including social stress arising from feeder competition and nutritional stress caused by prolonged fasting periods. Increased feeding frequency reduces aggressive interactions, whereas stable nutrient supply supports immune competence and gut integrity, thereby enhancing overall stress resilience (Wang et al., 2024).

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Conclusion

Feeding performance and reproductive and adaptive behavior in poultry are influenced by factors such as feeding hours and feeding rates. When feeding is well timed, metabolism and feeding behavior can be optimally optimized so that body weight gain, FCR, and flock uniformity will be in the upper range. Correctly scheduled feeding also facilitates follicle development, increased egg production, and improved egg quality, fertility, and hatchability. Under heat stress, adapting FTF can reduce heat production, preserve feed intake, protect the gut, and enhance stress tolerance among all FTF treatments used throughout the duration of heat stress. The principle summary and guidance is that optimizing FTF brings all-around benefits in terms of poultry performance and welfare in every production system, which should be adapted to the breed, age of birds, and environmental conditions of every production system. Given the diversity of poultry production systems worldwide, the recommendations provided in this review are intended as guiding principles rather than fixed feeding protocols. Future research should focus on identifying strain-specific and climate-adapted FTF strategies, integrating precision feeding technologies, and real-time monitoring to further enhance poultry productivity, welfare, and sustainability.

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Acknowledgment

We acknowledge the support of time and facilities from Tra Vinh University (TVU) for this study.

Conflict of interest

The authors declare that there is no conflict of interest.

Funding

None

Authors' contributions

Qui, N.H. and Linh, N.T.: Research design; Linh, N.T.: Data analysis; Qui, N.H.: Methodology; Qui, N.H. and Linh, N.T.: Validation; Linh, N.T.: Investigation; Qui, N.H., Linh, N.T.: Data curation; Qui, N.H.: Writing-original draft preparation; Qui, N.H., and Linh, N.T.: Writing—review and editing. All authors have read and approved the published version of the manuscript.

Data availability

All data provided in the manuscript.

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